Like Handles said, first off we need to know if you bow is set up properly. What kind of setup do you have??? If it is properly setup it is likely an issue of proper and consistant achor point and perhaps plain lack of practice and experience. Once you get set up properly and maintain a consistent achor point you might be shooting circles around your brother.

a baseball bat to your brothers knees should even the playing field.................just kidding dont do that, try slipping him some exlax